[EM] Condorcet strategy

[James Green-Armytage]

I wrote:
>What if some supporters of C managed were able to start a rumor
> that the A or B voters were planning to strategically truncate when in
> fact they were not?
Ernie wrote:
>If I understand you correctly, I believe the proper defensive response 
>to threatened order-reversal under Condorcet wv is simply equal-ranking 
>(one of the major reasons to allow equal-ranking, in fact). 


	Yes, I've discussed equal ranking under these circumstances quite a bit.
However, my point was that if members of both the A and B factions
truncate, C will end up winning the election. Especially in this example
27: A>B>C
25: B>A>C
24: C>A>B
24: C>B>A
>
	Assume that no one knows ahead of time who will win the A:B contest. If
somehow the A voters got paranoid that the B voters will order-reverse,
and the B voters get paranoid that the A voters will order reverse, and
only 5 of them on each side try 'defensive' truncation, the Condorcet
loser C will take the election.
	You're probably aware of this, but equal-ranking / truncation as a
counterstrategy against order reversal doesn't lead to the election of the
Condorcet winner, it leads to the election of both groups' least favorite
candidate (C in this case). Hence, actually truncating doesn't do any
good, it only makes things worse. 
	The only benefit that can be associated with 'defensive' truncation is
that it serves as a threat against people who are thinking about a
burial:reversal strategy. However, if you only have a single-round system,
it may be hard for such a threat to do any good, since there is no way to
assure that the behavior you would like to punish has occurred until it is
already too late to punish it (i.e. the election is over). This is one of
the main points I made in my May 26 posting ("Condorcet strategy and
anti-strategy measures").
	For truncation to be effective as a threat, and to result in the election
of A (the sincere Condorcet winner) you would have to find out that the B
people were planning to reverse, then you would have to somehow
communicate with them that if they keep talking about reversal, you will
try to get your group to truncate to result in the election of C. Then you
have to somehow receive some sort of assurance from the B people that they
will abandon their truncation plan and vote sincerely B>A>C... But what if
the B voters were lying, or the ones that said they wouldn't reverse
didn't actually speak for all the B voters, and a lot of actually went
ahead and reversed anyway on election day, tipping the result to B after
all? And so on. Communication is very difficult when you're dealing with
the sort of huge masses of people who would be playing this game in a big
public election. And in the absence of communication, cooperation becomes
more difficult.
	I think that a two-round system would help with this particular issue
because it would make just a little bit of room for an action-and-reaction
of strategy and punishment. A multiple-round system would help more, but
that's difficult for a public election. (These are basically game theory
concepts: cooperation tends to improve with better communication and more
rounds being played.)
>
>If fact, If I might make a friendly suggestion: Google is the best way 
>to track down all these acronyms (I'd suggest putting it in your 
>browser toolbar ).   For example, Googling "ATLO election-methods" 
>quickly pulls up "automatic trunation line option".

	Good suggestion. I'm also realizing that the gmane archive interface has
a search feature. I usually use the electorama archive for most purposes,
but I can use the gmane one when I need to do a search. Admittedly few to
none of us on this list are totally innocent of jargon-use, myself
included.

>Yeah, I'd love to see everyone on this list be more helpful and 
>considerate towards newcomers -- and old-timers, for that matter -- 
>but, alas, election method expertise is not always correlated with 
>emotional sensitivity.  We just have to play the cards we're dealt.

	I've had quite a few insults thrown at me lately, which is never
pleasant. I've given some too, but I think not as many as I've taken. 
	I especially don't appreciate the ones that say that I'm repeating myself
without reading what people have said in replies to my earlier statements,
because I try very hard to consider people's replies carefully and to
engage the discussion in good faith. 
	I guess that all of that is pretty much a side issue, though. I do
apologize to the people who find it distracting. I'm trying not to be too
distracted by it myself.
>
best,
James